Cancel task in Grand Central Dispatch GCD with DispatchWorkItem in Swift Hindi tutorial
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- Опубліковано 2 сер 2024
- DispatchWorkItem class in swift can be used when you want to cancel a task queued in grand central dispatch GCD. Mostly a question which is asked in interviews is if you can cancel a task in GCD and we say no and prefer to use Operation queues for that but you can actually allocate your task in DispatchWorkItem class and based on your logical or business condition cancel it whenever you see fit.
In this video, we will be seeing a real project scenario where you can use DispatchWorkItem to cancel and task and to optimize an existing module. We will learn how we can use the debounce technique and improve our code with DispatchWorkItem and DispatchQueue.
Given are the chapters covered in this video
0:00 introduction
0:14 prerequisite
0:48 complain about gcd
1:16 dispatchWorkItem class
1:23 codecat15 example
2:03 Pseudocode dispatchWorkItem
2:24 dispatchWorkItem example
4:45 dispatchWorkItem cancel example
8:51 real project scenario for using dispatchWorkItem
10:25 issue with the current implementation
11:02 debounce explanation
11:40 implementing debounce approach
12:48 need for work item reference explained
13:26 creating a work item reference
13:59 code explanation
14:36 debounce in action
16:00 conclusion
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#dispatchWorkItem #gcd #threadingInSwift
Sir, you are a real gem for the iOS developers. 🙏
Thank you 😊 I am glad the video was helpful. Plz do ask questions on this topic and do share the video with your iOS group
@@CodeCat15 Sir pls make more videos on concurrency on iOS like Operation Queues and some more advanced concepts if possible. Thanks.🙏
Sure will do Polu
Trust me this is my first comment in any ios development video , amazing explanation
Welcome to the channel Goving and thank you for taking time and commenting on the video, I am glad the contents of this channel are helpful :)
Great content sir. Grateful to access such content for free.
Hey Ravi, I don't have words for how to thank you. Just ming blowing bhava!
Akshay, welcome bhava, tula kahi doubts asel tar te pan vichar ani tuja iOS group sobat pan he channel share kar 👍
Great topic with great example and explanation! Very helpful.
Thanks Dhaval, glad the content is helpful. Do share the video with your iOS group and feel free to ask questions on the topic
Thank you for this video.
Awesome Video
Thanks for share brother
yes bro I learned new concept DispatchWorkItem from this video . Thank you :-)
Am glad this was helpful 👍
Excellent explanation. These videos are fulfilling the gap for me of not being trained professionally as trainee and using random techniques, internet solutions to solve problems in task deadline and later sit and regret for writing bad code and waste further more time to clean the previous code. I am feeling a technical detox by watching several of these videos on daily basis. Kudos to the creator. #CheersToCodeCat15
I like the term technical detox, funny thing is implementing clean code takes a little time but has long term benefits specially with regards to change requests, we surely don't want our codebase to be like a card house, you remove or replace one card and the entire house collapses.
Way of explaining 🙏🙂
Superb sir 👌👌
Bhai ekdum mst sikhato ho, thank you🙏🙏🙏
Thanks Neeraj, koi question raha ye topic pe to please puchna zaroor aur aapne iOS group mai bhi is video ko share karna :)
Very well done
Brilliancy ,bhai please do more and more videos ,,,,
Threading playlist link: ua-cam.com/play/PLb5R4QC2DtFuSE3wpJAqvFRbal5-7sAwr.html
Hope it helps
@@CodeCat15 ya bhai making notes out of all videos from the playlist... Thanks bahi really, har baar interview ma a topic pareshaan karta tha ....now it will not...
Awesome 😎
clear all my doubt Thank you sir.
You are most welcome
Ravi, you are Super.
Thank you Ashish :)
Very useful content.. keep rocking
Thanks a lot Sharmi
👌👌👌
informative
Thanks for this information. Please create a video on operation queue also
Hello Prashant, welcome to the channel I am glad this video was helpful. Please do feel free to ask questions on this topic and yes a video on operation queue and other threading concepts are on their way very soon
I Think in iOS 13 there is a debounce api but thanks for the video, i learned how it works
Indeed Somendra, using the combine framework we surely can implement debounce, but its from ios 13 onwards wish there was backward compatibility but its alright we have DispatchWorkItem to the rescue. Please feel free to ask questions on the topic and do share the channel with your iOS group
Very informative video Ravi....One doubt -> If we can cancel the task in GCD then what is the use of OperationQueue over it?
i made a video about this, please check it out and let me know if you have any queries
video link: ua-cam.com/video/JuFAW7y8lp0/v-deo.html
@@CodeCat15 Thank you Ravi🙂
nice vide0
Thank you :)
Bhai ek request hai apko code font is like android bro so change it to natural iOS. Thanks for content it was worthfull.
Mai initially asp.net developer tha aur hum visual studio use karte the jiska default font hai consolas aur abhi 10 saalo se vahi font ki adat ho chuki hai koi bhi editor ho meri font family fixed hai, maine try kiya tha xcode ka default font but then jama nahi mujhe sorry agar font ka vajaha se koi dikkat aai aapko 🙏
@@CodeCat15 Nahi bro I also had experience with Visual studio and remember this font haha 😛. no issues.
Brother
I did not get this can someone please explain me.
How DispatchWorkItem is cancelling the task? isCancellled bool which we checking here in for loop this bool variable is used for cancelling this for loop task (even cancelling by developer using break) not workitem.
Same task can achieve by published cause publishe has time & cancel property.
That’s more swiftui and am yet to explore that world of swiftui but it will be very interesting to see that and how it works or how it’s different from dispatchWorkItem I’ll make a note of this Sameer thanks for sharing ☺️
One difference between dispatch work item and operation queue is -
Dispatch work item can execute and cancel only one operation, whereas an operation queue can execute multiple operations concurrently and cancel together all if needed using the cancelAllOperations() method.
Is that correct ?
Apple recommends that you should always use the highest level of abstraction, which means we should be using operation queue and not GCD which is a low level api, but due to convince many devs including me go for gcd directly.
Having said that, operation queue holds its place coz it can handle dependencies and you can pause and yes cancel all operations, operation queue does things more object oriented way than GCD and we have more control over what we are trying to do with operation queue than GCD
Can we cancel api call in dispatchworkitem?
You can cancel the work item itself which will ultimately cancel whatever workItem it was intent to do
What this means is the API call which is already done to the server that call may happen and say before you receive the response if you cancel the workItem then in that case the response will be ignored.
In theory I believe this is what should happen but you can try this out and confirm if this works as per your given usecase.
Why are we calling the API on main queue?
Hey Keertika, url session internally calls the api on a background thread on its own so we don’t really have to specify or use a dispatch queue. If you watch the serial api call video there you can see this behavior
Video link: ua-cam.com/video/II7bJmC64IY/v-deo.html
Let me know if that answers your question and if not plz feel free to ask more.
@@CodeCat15 Thank you sooo much 😊
hello, I really enjoy your video.. so informative.. and to the point. hats off to you.
It would be really helpful if you create a video on the topic of the different combination of sync and async block using different dispatch queues(serial, concurrent, main &global). I really got confused of the flow in some of the questions like below,
func testx(){
defer {
print("--testx--")
}
DispatchQueue.main.async {
print("testx")
}
print("--testx")
}
func testy(){
defer {
print("--testy--")
}
DispatchQueue.main.async {
print("testy")
}
print("--testy")
}
func test(){
print("01")
testx()
print("02")
testy()
print("03")
}
test()
this will print:
01
--testx
--testx--
02
--testy
--testy--
03
testx
testy
here the dispatch asyn block executed at last why that so?
Yep, I also face the similar problem in understanding this topic. @CodeCat please answer
Let me make a video on this as comments could get a little lengthy
@@CodeCat15 sure, that'll be great.